Enhanced control of construction equipment

ABSTRACT

Novel tools and techniques for controlling heavy equipment vehicles, such as tractors, graders, road-forming machines, and the like. Some techniques allow a control system of a heavy equipment vehicle to transition from receiving position data from one positioning device to receiving data from another without ceasing operation and/or while limiting any resulting discontinuity in a manipulated ground surface to within acceptable tolerances.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/225,706, filed Mar. 26, 2014, by Jason Grier Lindsay Hill, et al. andtitled, “Enhanced Control of Road Construction Equipment,” which ishereby incorporated by reference in its entirety.

This application may be related to U.S. application Ser. No. 14/225,702,filed on Mar. 26, 2014, by Alan Sharp titled “Blended PositionSolutions” and assigned to Trimble Navigation, Limited (the “BlendedSolutions Application”), the entire disclosure of which is incorporatedby reference herein.

COPYRIGHT STATEMENT

A portion of the disclosure of this patent document contains materialthat is subject to copyright protection. The copyright owner has noobjection to the facsimile reproduction by anyone of the patent documentor the patent disclosure as it appears in the Patent and TrademarkOffice patent file or records, but otherwise reserves all copyrightrights whatsoever.

FIELD

The present disclosure relates, in general, to road construction, andmore particularly, to enhanced control systems that can employ multiplepositioning devices for control of equipment.

BACKGROUND

A variety of different machines are used in the construction of roadsand other infrastructure. Such machines (referred to collectively hereinas “road-forming machines”) can include, without limitation, equipmentthat displaces, shapes, and/or forms the underlying roadbed, such asearthmovers, motor graders and the like. Road-forming machines can alsoinclude machines that deposit and/or form the actual roadway material,such as asphalt pavers, which deposit asphalt on a road surface,slipform pavers, which extrude or otherwise shape concrete on a roadsurface, and/or the like. Such road-forming machines are commonlycontrolled by advanced control systems that use high-precisionpositioning equipment to ensure that the machines shape the earth and/orthe road surface consistent with an engineer's model for the project.

In some cases, such machines might include onboard positioningequipment, such as a global navigation satellite system (“GNSS”)receiver. Generally, however, such receivers do not provide the level ofprecision necessary for these types of projects. As a result, many suchsystems employ external positioning devices, such as total stations (ofwhich many are commercially available from Trimble Navigation) toprovide precise positioning information to the machine's control system.The use of such external devices, while providing precise positioninginformation, is not problem-free. For example, in many cases, a totalstation (or other positioning device) will need to be moved from onelocation to another, in order to continue to provide valid positioninginformation to the road-forming machine as the machine moves along thepath of a road. Typically, the machine will have to cease operationwhile the positioning device is moved and calibrated at the newlocation. This interruption greatly reduces the efficiency of theconstruction operation, adding time and expense to the project. Thisinefficiency can be mitigated somewhat through the use of multiplepositioning devices, but the inability of a control system to receiveinput from more than one device simultaneously means that the machinewill still have to cease operation while it transitions from onepositioning device to another.

Further, every time the positioning device is moved in such projects, ora control system switches from one positioning device to another, anyerror in the data received from either device can introduce adiscontinuity in the road surface. Such errors can result fromimprecision of the calibration of positioning devices, thermal effects(which can cause minor distortion of lasers used to determine themachine's position by the positioning devices), wind and otherenvironmental effects, and the like. Continuity of the road surface isoften of primary importance (to whatever degree of precision isappropriate, depending on the step in the process). Merely by way ofexample, in many cases, there is a relatively large degree of freedom invariance from the model of the project, so that a road surface a fewcentimeters higher lower than the elevation specified by the model isacceptable. On the other hand, a discontinuity of even a centimeter inthe surface of a road can create significant issues (the least of whichis a severe bump for any cars that travel the road). Hence, conventionalsystems further degrade efficiency by requiring additional processes toprevent or remedy such discontinuities.

Accordingly, there is a need for control systems for road-formingmachines that provide more robust positioning control.

BRIEF SUMMARY

Certain embodiments provide improved tools and techniques forcontrolling road-forming machines. In an aspect of particularembodiments, these tools allow a control system of a road-formingmachine to transition from receiving position data from one positioningdevice to receiving data from another without ceasing operation and/orwhile limiting any resulting discontinuity in the formed road surface towithin acceptable tolerances. The tools provided by various embodimentsinclude, without limitation, road-forming machines, methods, computersand control systems, and/or software products. Merely by way of example,a method might comprise one or more procedures, any or all of which areexecuted by a computer system. Correspondingly, an embodiment mightprovide a computer system configured with instructions to perform one ormore procedures in accordance with methods provided by various otherembodiments. Similarly, a computer program might comprise a set ofinstructions that are executable by a computer system (and/or aprocessor therein) to perform such operations. In many cases, suchsoftware programs are encoded on physical, tangible and/ornon-transitory computer readable media (such as, to name but a fewexamples, optical media, magnetic media, and/or the like).

Merely by way of example, a road-forming machine (which might be apaving machine, such as a concrete paver, asphalt paver, slip-formpaver, and/or the like; milling machine; motor grader; scraper; or anyother machine capable of forming a road surface and/or the earth onwhich a road surface will be built) in accordance with one set ofembodiments might comprise a locomotion system configured to move theroad-forming machine, which can include, without limitation, wheelsand/or tracks, as well as the apparatus for providing power and/orsteering input to such wheels and/or tracks. The road-forming machinemight also comprise a road-forming system configured to form a roadsurface continuously as the road-forming machine moves; the road-formingsystem might include, without limitation, a grader blade, a pavingsystem, and/or the like.

In some cases, the road-forming machine might comprise a communicationinterface to provide communication with a plurality of positionmeasurement devices and/or a control system comprising a processor, anon-transitory storage medium, and a set of instructions executable bythe processor. Such instructions can include, without limitation,instructions to cause the road-forming machine to implement methodsprovided by other embodiments. Merely by way of example, in someembodiments, the set of instructions might comprise instructions toreceive position data from one or more position measurement devices,including a first position measurement device and a second positionmeasurement device. The set of instructions might further compriseinstructions to control operation of the road-forming system, forexample, based on determined positions of the road-forming system and amodel stored on the non-transitory storage medium.

There might be further instructions to determine a first position of theroad-forming system based on position data received from the firstposition measurement device, instructions to transition from the firstposition measurement device to the second position measurement device,and/or instructions to determine a second position of the road-formingsystem based on position data received from the second positionmeasurement device. In some cases, the transition from the firstposition measurement device to the second position measurement devicecan be accomplished without interrupting movement of the road-formingmachine or formation of the road surface and/or without introducing adiscontinuity in the formed road surface greater than a specifiedthreshold value.

Another set of embodiments provides computer systems, including withoutlimitation control systems for road-forming machines. One exemplarycontrol system might comprise one or more processors and anon-transitory computer readable medium in communication with the one ormore processors. A further set of embodiments provides apparatus, whichcan include without limitation, a non-transitory computer readablemedium having encoded thereon instructions for programming such acontrol system. In either case, the computer readable medium havingencoded thereon a set of instructions executable by the computer systemto perform one or more operations, including without limitationoperations consistent with methods provided by various embodiments.

An exemplary set of instructions might comprise instructions to receiveposition data from two or more position measurement devices, including afirst position measurement device and a second position measurementdevice. The set of instructions could further include instructions tocontrol operation of a locomotion system of the road-forming machine anda road-forming system of the road-forming machine to form a road surfacecontinuously, e.g., based on determined positions of the road-formingsystem and a model stored on the non-transitory computer readablemedium. The set of instructions might also include instructions todetermine a first position of the road-forming system based on positiondata received from the first position measurement device, instructionsto transition from the first position measurement device to the secondposition measurement device, and/or instructions to determine a secondposition of the road-forming system based on position data received fromthe second position measurement device. In some cases, this transitioncan be performed without interrupting movement of the road-formingmachine or formation of the road surface, and/or without introducing adiscontinuity in the road surface greater than a specified thresholdvalue.

Yet another set of embodiments provides methods. One exemplary methodmight comprise forming a road surface with a road-forming machine, suchas those described herein. Merely by way of example, a road-formingmachine might comprise a locomotion system configured to move theroad-forming machine, a road-forming system configured to form a roadsurface continually as the road-forming machine moves, a communicationinterface to provide communication with a plurality of positionmeasurement devices, and/or a control system configured to controloperation of the road-forming machine.

The method, then, might comprise receiving, e.g., with the controlsystem, position data from two or more position measurement devices,including a first position measurement device and a second positionmeasurement device. In some cases, the method further comprisescontrolling, with the control system, operation of the locomotion systemand the road-forming system, for example, based on determined positionsof the road-forming system and a model stored on the non-transitorystorage medium. In particular embodiments, the method can includedetermining, with the control system, a first position of theroad-forming system based on position data received from the firstposition measurement device; transitioning, with the control system,from the first position measurement device to the second positionmeasurement device; and/or determining a second position of theroad-forming system based on position data received from the secondposition measurement device. In a particular aspect, the transitioningoperation can occur without interrupting movement of the road-formingmachine or formation of the road surface and without introducing adiscontinuity in the formed road surface greater than a specifiedthreshold value.

BRIEF DESCRIPTION OF THE DRAWINGS

A further understanding of the nature and advantages of particularembodiments may be realized by reference to the remaining portions ofthe specification and the drawings, in which like reference numerals areused to refer to similar components. In some instances, a sub-label isassociated with a reference numeral to denote one of multiple similarcomponents. When reference is made to a reference numeral withoutspecification to an existing sub-label, it is intended to refer to allsuch multiple similar components.

FIG. 1 illustrates a system for providing positioning information to aroad-forming machine, in accordance with various embodiments.

FIG. 2 is a simplified block diagram illustrating a generic road-formingmachine, in accordance with various embodiments.

FIG. 3 illustrates a paving machine, in accordance with variousembodiments.

FIG. 4 illustrates a motor grader, in accordance with variousembodiments.

FIG. 5 is a process flow diagram illustrating a method of controlling aroad-forming machine, in accordance with various embodiments.

FIG. 6 is a generalized schematic diagram illustrating a computersystem, in accordance with various embodiments.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

While various aspects and features of certain embodiments have beensummarized above, the following detailed description illustrates a fewexemplary embodiments in further detail to enable one of skill in theart to practice such embodiments. The described examples are providedfor illustrative purposes and are not intended to limit the scope of theinvention.

In the following description, for the purposes of explanation, numerousspecific details are set forth in order to provide a thoroughunderstanding of the described embodiments. It will be apparent to oneskilled in the art, however, that other embodiments of the present maybe practiced without some of these specific details. In other instances,certain structures and devices are shown in block diagram form. Severalembodiments are described herein, and while various features areascribed to different embodiments, it should be appreciated that thefeatures described with respect to one embodiment may be incorporatedwith other embodiments as well. By the same token, however, no singlefeature or features of any described embodiment should be consideredessential to every embodiment of the invention, as other embodiments ofthe invention may omit such features.

Unless otherwise indicated, all numbers used herein to expressquantities, dimensions, and so forth used should be understood as beingmodified in all instances by the term “about.” In this application, theuse of the singular includes the plural unless specifically statedotherwise, and use of the terms “and” and “or” means “and/or” unlessotherwise indicated. Moreover, the use of the term “including,” as wellas other forms, such as “includes” and “included,” should be considerednon-exclusive. Also, terms such as “element” or “component” encompassboth elements and components comprising one unit and elements andcomponents that comprise more than one unit, unless specifically statedotherwise.

Certain embodiments provide improved tools and techniques forcontrolling road-forming machines. In an aspect of particularembodiments, these tools allow a control system of a road-formingmachine to transition from one positioning device to another withoutceasing operation and while limiting any resulting discontinuity towithin acceptable tolerances. For example, FIG. 1 (which is not drawn toscale) illustrates a system 100 for providing position information to aroad-forming machine 105. As noted above, such road-forming machines 105can include any number of machines or vehicles, such as, withoutlimitation, equipment that displaces, shapes, and/or forms theunderlying roadbed, such as earthmovers, milling machines, motorgraders, and the like, as well as machines that deposit and/or form theactual roadway material, such as asphalt pavers, which deposit asphalton a road surface, concrete pavers, slipform pavers, which extrude orotherwise shape concrete on a road surface, and/or the like. In theexample illustrated by FIG. 1, the road-forming machine 105 might be anasphalt paver that deposits asphalt on an existing surface of a road 110to improve that surface.

Typically, most road-forming operations (whether creating the underbedor applying the road surface) are designed using advanced modelingsoftware, such as the Trimble Office™ package commercially availablefrom Trimble Navigation Ltd. Using such software, an engineer can createa model for the road that accounts for the topography of the area, anytechnical or regulatory constraints (such as maximum allowable grade,and the like), and any other design features of the project. Such modelsgenerally are oriented to a local or (more likely) global coordinatesystem, such as latitude/longitude/elevation. The road 110, then, isformed consistently with this model, to whatever degree of precision isrequired.

To ensure consistency between the formed road 110 and the design model,the location of the road-forming machine 105 relative to the coordinatesystem in use must be carefully managed. There are several techniquesfor managing the location of the machine 105. For example, the controlsystem of the machine 105 itself might include a global navigationsatellite system (“GNSS”) receiver. Generally, however, an onboard GNSSreceiver does not provide the precision necessary to conformsufficiently to the established model for the road 110. Accordingly, anaccepted practice is to track the position of the machine 105 with oneor more high-precision position measurement devices 115 (also referredto herein as “positioning devices”). Such position measurement devices115 can include, without limitation, total stations such as thoseavailable from Trimble Navigation Ltd., rovers such as those disclosedin U.S. Pre Grant Pub. No. 2012-0166137-A1, the descriptions of whichare incorporated herein by reference, or any other device capable ofproviding an external reference of the machine's 105 position. Such aposition measurement device, e.g., 115 a, after determining the positionof the machine 105 (through whatever technique) can then communicatethat position information to the control system of the machine 105.

A variety of techniques are available for a position measurement device115 to communicate position information to the machine 105. In somecases, standard communication interfaces, such as IEEE 802.11x (WiFi)radios or cellular radios, might be installed in the positionmeasurement device 115 and the control system of the machine 105. Inother cases, proprietary single- or multi-channel radios might providesuch communication. In any case, the position measurement device 115provides position information to a control system (which might belocated, but need not necessarily be located on the machine 105), whichdetermines the position of the machine 105 based on the positioninformation received from a position measurement device, such as device115 a.

As the machine 105 moves along the road, however, the position solutionprovided by a particular position measurement device 115 a mightdegrade, because of the distance between the machine 105 and the device115 a, obscured sightlines between the machine 105 and the device 115 a,or various other factors. Accordingly, the machine will need to obtainposition information from a different position measurement device, e.g.,115 b (which can be a different device from the device 115 a or can bethe same device moved to a different station). This process cancontinue, using devices 115 c and 115 d in sequence as the machine movesdown the road 110. In a particular aspect, two (or more) devices mightbe used in a leapfrog fashion, such that a single position measurementdevice might serve as device 115 a and device 115 c, while anotherposition measurement device might as device 115 b and device 115 d.

Conventionally, the transition from obtaining position information fromone device 115 to obtaining position information from another device 115(or from the same device 115 at a different station) requires themachine 105 to be stopped and recalibrated. Further, because of minorerror in the position solutions provided by one or the other (or both)of the devices 115, the calculated position of the machine 105 mightexperience a discontinuity during the transition. As noted above, boththe need to cease operations and the potential for discontinuity canpresent problems for the project. Various embodiments, as described infurther detail below, can avoid these problems by allowing the machine105 to transition from one position measurement device (e.g., 115 a) toanother device (e.g., 115 b) without ceasing operation and whilemaintaining continuity (to within a specified precision) in thecalculation of the position of the machine 105.

FIG. 2 is a simplified block diagram illustrating a generic road-formingmachine 200, in accordance with various embodiments. (It should be notedthat, although the description herein generally refers to road-formingmachines, embodiments are not so limited, and various embodiments can beused to control any type of vehicle, in including in particular heavyequipment vehicles, which include road-forming machines and otherconstruction equipment, tractors, heavy-duty trucks, and the like.) Thegeneric road-forming machine can represent any suitable type of machine,including without limitation those described above, as well as thespecific (but not limiting) examples depicted in FIGS. 3 and 4. Thegeneric machine 200 comprises a locomotion system 205. The locomotionsystem 205 can include any components that provide movement for themachine 200, including without limitation engine, drivetrain,suspension, wheels, tracks (or other ground-contact components),steering systems and components, braking systems and components, and/orthe like. The machine 200 might further comprise a road-forming system210, which can include any of a variety of tools or components designedto form, shape, move, extrude, compact or otherwise manipulate a groundsurface, such as a dirt underbed for a road, a paving material (e.g.,concrete, asphalt, etc.).

In an aspect, the machine 200 further comprises a control system 215,which can comprise a special-purpose computer or a programmedgeneral-purpose computer (general examples of which are described belowwith regard to FIG. 6). The control system 215 communicates with varioussystems of the machine 200 (including without limitation those describedabove) and controls the operation of the machine 200, including withoutlimitation the operation of the locomotion system 205 and theroad-forming system 210. As noted above, the locomotion system 205 andthe road-forming system 210 each can include a variety of components,and the skilled reader should appreciate that and/or each system 205,210 can perform one or more functions; for instance, the locomotionsystem 205 perform steering functions, horizontal and/or verticalmovement functions, and the like. As used herein, the term “control”(and its derivatives), when applied to controlling such systems, meansproviding control input for one or more functions performed by one ormore components of such a system. Thus, for example, when controllingthe locomotion system 205, the control system 215 might provide controlinput to the locomotion system 205 with regard to forward velocity ofthe machine 205 based on the techniques described herein, but might notprovide control input for a steering function (which might be controlledby an operator), or vice versa.

In some respects, the control system 215 operates in response tooperator input, while in other respects, the control system 215 providesautomated control over machine 200 operations. In particularembodiments, for example, the control system 215 can be loaded with adesign model for the project and can operate the machine 200, largelyautonomously, to conform with the design model. In other cases, thecontrol system 215 might involve more user interaction; for example, thecontrol system might accept user input to modify parameters specified bythe model to account for site-specific conditions or events, and/or thecontrol system, rather that providing autonomous control over othermachine 200 systems, might provide guidance to an operator who manuallycontrols such systems.

The machine 220 can also include a communications interface 220, whichmight be integrated with the control system 215 or otherwise incommunication with the control system 215. The communication interface220 can include any hardware or software necessary to providecommunication between the control system 215 and external devices, suchas ports for wired communication (e.g., serial ports, Ethernet ports),wireless radios (e.g., Bluetooth™ radios, 802.11x radios, cellularradios and other standard or proprietary radio frequency (RF)communication radios). In an aspect, the communication interface 220provides connectivity between the machine 200 (or more precisely, thecontrol system 215) and various data sources, including office computersand field computers (which can be used to upload the project designmodel to the control system 215) and position-measurement devices, fromwhich the control system 215 can receive position data (e.g., asdescribed in further detail below) to ensure that the as-built projectremains consistent with the design model.

It should be appreciated that the machine 200 depicted in FIG. 2 isillustrated, and described, with a high degree of generality, and that atypical road-forming machine will have many other components andsystems. The machine 200 is described herein merely for purposes ofillustrating the concepts of certain embodiments with regard tocontrolling a wide variety of road-forming machines, which necessarilywill feature different types of systems and components to accomplishvarious road-forming tasks.

For instance, FIG. 3 illustrates a paving machine 300, in accordancewith various embodiments, which can be considered one specific type ofroad-forming machine, which can form a road surface by depositing and/orextruding paving material to form a road surface. The paving machine 300might be a slipform paver (or “white paver”) that extrudes concreteprovided by separate vehicles, or it might be an asphalt paver thatdeposits asphalt from a hopper on the machine 300 itself. In eithercase, the paving machine might have a locomotion system that comprises aset of tracks 305, which provide locomotion of the machine 300. Thepaving machine 300 might also comprise a communication interface and/ora control system which are (not illustrated on FIG. 3 but describedabove with respect to FIG. 2). The control system, for example, cancontrol operation of the locomotion system (including the tracks), forexample, by controlling a speed of the tracks and/or steering of themachine through the tracks, in accordance with the techniques describedin further detail below.

Additionally, the paving machine 300 might comprise a paving system,which can include apparatus 310 for depositing, extruding, and/orotherwise forming a paving material on a road surface, as well as a setof legs 315 that control a height of the apparatus 310 from the groundsurface on which the tracks 305 are situated. The control system cancontrol various aspects of this paving system, for example to set anelevation of the top surface of the paving material, to control thespeed at which paving operations are performed, and/or the like.

FIG. 4 illustrates a motor grader 400, in accordance with variousembodiments, which can be considered another example of a road-formingmachine, and which can form a road surface, e.g., by removing and/ormoving material to form an underbed of the road surface, and/or bymoving and/or removing material from the road surface itself. Like thepaving machine described above (and all road-forming machines moregenerally), the motor grader 400 can include a control system and/or acommunication interface (not illustrated on FIG. 4), which can functionas described above with regard to FIG. 2. The motor grader 400 mightalso include a locomotion system, which can include wheels 400, as wellas an engine, drivetrain, steering system, and/or the like, as well as aroad-forming system, which in this case can include a scraper blade 410and apparatus for orienting the scraper blade 410. Both the locomotionsystem and the road-forming system can be controlled by the controlsystem, as described above with respect to FIG. 2.

Although FIG. 2 illustrates a road-forming machine in general, and FIGS.3 and 4 illustrate specific examples of such machines, the skilledreader should understand that embodiments are not limited to thesespecific examples. Rather, embodiments can include any type ofroad-forming machine (or any type of machine more generally) that canoperate in accordance with the techniques and principles describedherein. For example, FIG. 5 illustrates a method 500 of controlling aroad-forming machine in accordance with one set of embodiments. Whilethe techniques and procedures of FIG. 5 are depicted and/or described ina certain order for purposes of illustration, it should be appreciatedthat certain procedures may be reordered and/or omitted within the scopeof various embodiments. Moreover, while the method illustrated by FIG. 5can be implemented by (and, in some cases, are described below withrespect to) the systems (including without limitation control systems)and machines illustrated by FIGS. 1-4 (or components thereof), thesemethods may also be implemented using any suitable hardwareimplementation. Similarly, while the systems of FIGS. 1-4 (and/orcomponents thereof) can operate according to the methods illustrated byFIG. 1 (e.g., by executing instructions embodied on a computer readablemedium), the systems can also operate according to other modes ofoperation and/or perform other suitable procedures.

The method 500 of FIG. 5 might comprise storing, e.g., in a controlsystem, a design model for a road-forming project (block 505). As notedabove, such a model may be created by an office computer, or anotherappropriate device, and transmitted or otherwise uploaded to the controlsystem of a road-forming machine. (Alternatively, in some embodiments,the control system itself might be used to create or update a designmodel.) In an aspect, a design model can specify dimensions andpositions of project features. Merely by way of example, with regard toa road, the design model might specify latitude and longitudecoordinates for edges of the road and an elevation of the crown and/orthe edges of the road, with coordinates provided for various points(spaced as frequently as necessary) along the length of the road. Such amodel can be stored on a computer readable medium (e.g., by a controlsystem or other device) and can serve as a reference against which theproject or a project feature (e.g., a road) is built.

The skilled reader can appreciate that, in order to maintain fidelity tothe model, the road-forming machine must maintain an awareness of theposition of whatever road-forming system it includes (which generally isa function of the position of a reference point on the machine itself,such as the position of an optical target, a GPS receiver, and/or thelike), so that the formed road surface (or under bed, etc.)dimensionally and positionally satisfies the constraints imposed by themodel. As noted above, in some cases, the road-forming machine candetermine its own position using onboard facilities, but this techniqueoften does not provide sufficient accuracy and/or precision.

Hence, the method 500 can further include receiving (e.g., with acontrol system of a road-forming machine or other vehicle) position datafrom two or more position measurement devices (block 510). In somecases, the method 500 will include selecting one of the positionmeasurement devices from which to receive position data and/or to usethe received position data (block 515). A variety of techniques can beused to select which position measurement device's data should be usedby the control system, as described in further detail below.

The method 500, then, can include determining, at block 520, a firstposition of the road-forming machine (and/or the road-forming systemthereof). In an aspect of some embodiments, such a determination is madebased on the position data received from the selected positionmeasurement device. For instance, a particular embodiment, the positionmeasurement device might transmit to the control system a measuredposition of an optical target (or other reference point) on theroad-forming machine, and the control system might be programmed withinstructions to derive a position of one or more points of interest onthe machine (such as positions, in 3 dimensions, of each endpoint of abottom surface of a motor grader blade, of each lateral endpoint of anextrusion system or pavement deposition system, and/or the like). Suchpoints of interest might each have a known offset from the referencepoint, and, as such, the position of each such point can be known inrelation to the reference point. Hence, in determining the position ofthe road-forming machine, the control system might actually determinethe position of one or more such points of interest relative to theposition of the machine and/or a reference point thereon.

In some embodiments, the method 500 can further comprise controllingoperation of the road-forming machine and/or various systems thereof(block 525). More particularly, in some embodiments, the method caninclude controlling operation of a locomotion system and/or aroad-forming system, based on a comparison of positions of theroad-forming machine (and/or various points of interest thereof, asdescribed above) with reference points specified by the design model.This comparison can occur continuously and/or periodically (on whateverfrequency is appropriate to attain the desired precision of fidelity tothe model), and the operation of various systems can be adjusted basedon this comparison.

Merely by way of example, in the context of a paving machine, if themodel indicates that the road surface should curve beginning at acertain point, when the machine (or more particularly the paving systemthereof) reaches that point, the control system might adjust steering ofthe tracks of the paving machine to produce the curve specified by themodel. Similarly, the paving machine might adjust the height of one ofmore legs that support the paving system to ensure that the formed roadsurface conforms to an elevation specified by the model at thelatitude/longitude coordinates that the control system has determined tobe the position of the paving system a given point in time. To useanother example, the steering apparatus, wheel speed, and/or bladeposition/orientation of a motor grader can be controlled by controlsystem to ensure consistency of a graded surface to a model of thatsurface.

The control system might receive various forms of input and providevarious forms of output, other than merely receiving position data andproviding control output. For example, the control system might receiveuser input and/or provide output to a user. Accordingly, in some cases,the method 500 includes providing a user interface to provide for suchuser interaction (block 530). For example, the user interface can beused to output information for a user, e.g., by displaying theinformation on a display device, printing information with a printer,playing audio through a speaker, etc.; the user interface can alsofunction to receive input from a user, e.g., using standard inputdevices such as mice and other pointing devices, motion capture devices,touchpads and/or touchscreens, keyboards (e.g., numeric and/oralphabetic), microphones, etc. In some cases, the user interface mightbe provided in a cab of the road-forming machine. In other cases, thecontrol system might communicate with a remote device (such as a fieldcomputer), and the user interface might be implemented by such a remotedevice. In any case, the user interface can provide for various types ofuser interaction.

Merely by way of example, the method 500 can include displayinginformation with the user interface (block 535). Such information caninclude a variety of different types of data with regard to theoperation and or control of the road-forming machine. For instance, theuser interface might display information about operational parameters ofthe machine and/or the systems thereof, information about the designmodel and/or the machine's progress in implementing the model.

In a particular aspect, the user interface can display information aboutany position measurement devices with which the control system cancommunicate and/or from which the control system can receive positiondata. Such information can include, without limitation, a distance toeach of the position measurement devices from the current position ofthe machine, information about the location of each of the positionmeasurement devices (which could be presented graphically, e.g., as amap showing the identified position measurement devices and theroad-forming machine, and/or texturally, e.g., as positions of eachposition measurement device expressed in relation to the coordinatesystem used for the project, such as latitude/longitude/elevation). Suchinformation can also include an identification of which positionmeasurement device(s) currently provide the position data that is beingused to determine the position of the machine at that time.

Similarly, the method 500 might comprise receiving input (e.g., at thecontrol system) with the user interface (block 540). Such input caninclude control input for operation of the road-forming machine, and/orvarious systems thereof, such as input to begin road-forming operations,to cease road-forming operations, to power up or power down theroad-forming machine, to provide manual modification of the steering ofwheels or tracks, to provide manual control over a height of one or morelegs supporting a paving system, to manually control a position of amotor grader blade, and/or to otherwise provide manual operationalcontrol of the machine or any of its systems. Further, as noted below,the control system may be programmed to ensure that the formed roadsurface has no discontinuities greater than a particular tolerance, andthe user interface can receive user input to define such tolerances. Forexample, the control system might ensure that any such discontinuitiesdo not exceed a vertical and/or horizontal threshold value, the controlsystem might receive user input specifying vertical and/or horizontalthreshold values and/or an overall threshold value that should not beexceeded in this regard. As another example of a threshold, the controlsystem might have defined a minimum (or maximum) distance threshold overwhich discontinuities should be resolved. For instance, a distancethreshold could specify the linear distance over which any discontinuity(vertical or horizontal) is absorbed to mitigate surface or alignmentdiscrepancies.

In a particular embodiment, the user-interface can receive user input tospecify which position measurement device (of a plurality of identifiedposition measurement devices) should be used by the control system todetermine the position of the road-forming machine. Merely by way ofexample, as noted above, identified position measurement devices can beshown in a list, on a map, and/or the like, with associated information(such as location of each device, the distance from the machine of eachdevice, a signal strength of the signal received by the control systemfrom each device, etc.). The control system may be configured to allowthe user to select any such position measurement device as the device tobe used to determine the position of the road-forming machine, e.g., bytouching an identification of one of the position measurement devices ona touchscreen, scrolling through a list of devices with the cursor,selecting one of the devices with a mouse, and/or the like.

In an aspect, the method 500 might include selecting a new positionmeasurement device (of the plurality of such devices) from which toreceive position data (block 545). The control system might use one ormore of any of a variety of techniques to select the new positionmeasurement device from which to receive data to determine the positionof the machine. Merely by way of example, the control system mightmerely select a position measurement device that has been specified byuser input (e.g., as described above).

Alternatively and/or additionally, the control system mightautomatically (i.e., without user input) select a new positionmeasurement device based on any of a number of factors. For instance,the control system might select the closest position measurement device,the position measurement device with the strongest signal, and/or thelike. In some cases, the control system might take into account themovement of the machine and/or details of the design model to select anew position measurement device. For instance, the control system mightselect the closest position measurement device in the direction in whichthe machine is currently traveling, the closest position measurementdevice to a future position of the machine (as specified by the model),and/or the like. Based on the disclosure herein, the skilled reader willappreciate that the control system could use any of a variety ofdifferent decision matrices or algorithms to select a new positionmeasurement device.

The method 500, then, can also include transitioning from the originalposition measurement device to the selected position measurement device(block 535). In other words, the control system might switch from usingdata from the original position measurement device to determine themachine's position to using data from the newly-selected positionmeasurement device to determine the machine's position. Once thetransition to the selected position measurement device has beenperformed, the method 500 can include, at block 555, receiving positiondata from the selected position measurement device (as described above,for example) and can continue from block 520 with determining theposition of the machine or vehicle.

As noted above, a novel aspect of some embodiments is the ability totransition from one position measurement device without affectingoperation of the road-forming machine. Hence, in some cases, thetransition and/or position determination using data from a new positionmeasurement device can be performed without interrupting movement of theroad-forming machine or formation of the road surface. Alternativelyand/or additionally, this continuous performance of road-formingoperations can be accomplished without introducing a discontinuity inthe formed road surface greater than a specified threshold value (whichmight be specified, as noted above, through user input, or which mightbe specified by the model itself, by default parameters in the controlsystem, and/or the like).

To accomplish such a transition without affecting operations, thecontrol system might use any of a variety of techniques to allow for asmooth transition. Merely by way of example, the control system, forsome period of time (or while the machine travels some distance) mightreceive position data from the original position measurement device andthe new position measurement device and/or might determine a blendedposition solution based on some combination of the data from bothdevices, in order to minimize any discontinuities in the positionsolution based on differential error between the position data providedby each respective position measurement device. The Blended SolutionsApplication, already incorporated herein by reference, describes severaltechniques (any of which can be employed with the method 500) todetermine a blended position solution for the position of the machine ata given point in time.

FIG. 6 provides a schematic illustration of one embodiment of a computersystem 600 that can perform the methods provided by various otherembodiments, as described herein, and/or can function as a controlsystem for a road-forming machine or other vehicle, an office computer,a field computer, a control system for a position measurement device,and/or the like. It should be noted that FIG. 6 is meant only to providea generalized illustration of various components, of which one or more(or none) of each may be utilized as appropriate. FIG. 6, therefore,broadly illustrates how individual system elements may be implemented ina relatively separated or relatively more integrated manner.

The computer system 600 is shown comprising hardware elements that canbe electrically coupled via a bus 605 (or may otherwise be incommunication, as appropriate). The hardware elements may include one ormore processors 610, including without limitation one or moregeneral-purpose processors and/or one or more special-purpose processors(such as digital signal processing chips, graphics accelerationprocessors, and/or the like); one or more input devices 615, which caninclude without limitation a mouse, a keyboard and/or the like; and oneor more output devices 620, which can include without limitation adisplay device, a printer and/or the like.

The computer system 600 may further include (and/or be in communicationwith) one or more storage devices 625, which can comprise, withoutlimitation, local and/or network accessible storage, and/or can include,without limitation, a disk drive, a drive array, an optical storagedevice, solid-state storage device such as a random access memory(“RAM”) and/or a read-only memory (“ROM”), which can be programmable,flash-updateable and/or the like. Such storage devices may be configuredto implement any appropriate data stores, including without limitation,various file systems, database structures, and/or the like.

The computer system 600 might also include a communications subsystem630, which can include without limitation a modem, a network card(wireless or wired), an infra-red communication device, a wirelesscommunication device and/or chipset (such as a Bluetooth™ device, an802.11 device, a WiFi device, a WiMax device, a WWAN device, cellularcommunication facilities, etc.), and/or the like. The communicationssubsystem 630 may permit data to be exchanged with a network (such asthe network described below, to name one example), with other computersystems, and/or with any other devices described herein. In manyembodiments, the computer system 600 will further comprise a workingmemory 635, which can include a RAM or ROM device, as described above.

The computer system 600 also may comprise software elements, shown asbeing currently located within the working memory 635, including anoperating system 640, device drivers, executable libraries, and/or othercode, such as one or more application programs 645, which may comprisecomputer programs provided by various embodiments, and/or may bedesigned to implement methods, and/or configure systems, provided byother embodiments, as described herein. Merely by way of example, one ormore procedures described with respect to the method(s) discussed abovemight be implemented as code and/or instructions executable by acomputer (and/or a processor within a computer); in an aspect, then,such code and/or instructions can be used to configure and/or adapt ageneral purpose computer (or other device) to perform one or moreoperations in accordance with the described methods.

A set of these instructions and/or code might be encoded and/or storedon a non-transitory computer readable storage medium, such as thestorage device(s) 625 described above. In some cases, the storage mediummight be incorporated within a computer system, such as the system 600.In other embodiments, the storage medium might be separate from acomputer system (i.e., a removable medium, such as a compact disc,etc.), and/or provided in an installation package, such that the storagemedium can be used to program, configure and/or adapt a general purposecomputer with the instructions/code stored thereon. These instructionsmight take the form of executable code, which is executable by thecomputer system 600 and/or might take the form of source and/orinstallable code, which, upon compilation and/or installation on thecomputer system 600 (e.g., using any of a variety of generally availablecompilers, installation programs, compression/decompression utilities,etc.) then takes the form of executable code.

It will be apparent to those skilled in the art that substantialvariations may be made in accordance with specific requirements. Forexample, customized hardware (such as programmable logic controllers,field-programmable gate arrays, application-specific integratedcircuits, and/or the like) might also be used, and/or particularelements might be implemented in hardware, software (including portablesoftware, such as applets, etc.), or both. Further, connection to othercomputing devices such as network input/output devices may be employed.

As mentioned above, in one aspect, some embodiments may employ acomputer system (such as the computer system 600) to perform methods inaccordance with various embodiments of the invention. According to a setof embodiments, some or all of the procedures of such methods areperformed by the computer system 600 in response to processor 610executing one or more sequences of one or more instructions (which mightbe incorporated into the operating system 640 and/or other code, such asan application program 645) contained in the working memory 635. Suchinstructions may be read into the working memory 635 from anothercomputer readable medium, such as one or more of the storage device(s)625. Merely by way of example, execution of the sequences ofinstructions contained in the working memory 635 might cause theprocessor(s) 610 to perform one or more procedures of the methodsdescribed herein.

The terms “machine readable medium” and “computer readable medium,” asused herein, refer to any medium that participates in providing datathat causes a machine to operation in a specific fashion. In anembodiment implemented using the computer system 600, various computerreadable media might be involved in providing instructions/code toprocessor(s) 610 for execution and/or might be used to store and/orcarry such instructions/code (e.g., as signals). In manyimplementations, a computer readable medium is a non-transitory,physical and/or tangible storage medium. Such a medium may take manyforms, including but not limited to, non-volatile media, volatile media,and transmission media. Non-volatile media includes, for example,optical and/or magnetic disks, such as the storage device(s) 625.Volatile media includes, without limitation, dynamic memory, such as theworking memory 635. Transmission media includes, without limitation,coaxial cables, copper wire and fiber optics, including the wires thatcomprise the bus 605, as well as the various components of thecommunication subsystem 630 (and/or the media by which thecommunications subsystem 630 provides communication with other devices).Hence, transmission media can also take the form of waves (includingwithout limitation radio, acoustic and/or light waves, such as thosegenerated during radio-wave and infra-red data communications).

Common forms of physical and/or tangible computer readable mediainclude, for example, a floppy disk, a flexible disk, a hard disk,magnetic tape, or any other magnetic medium, a CD-ROM, any other opticalmedium, a RAM, a PROM, and EPROM, a FLASH-EPROM, any other memory chipor cartridge, a carrier wave as described hereinafter, or any othermedium from which a computer can read instructions and/or code.

Various forms of computer readable media may be involved in carrying oneor more sequences of one or more instructions to the processor(s) 610for execution. Merely by way of example, the instructions may initiallybe carried on a magnetic disk and/or optical disc of a remote computer.A remote computer might load the instructions into its dynamic memoryand send the instructions as signals over a transmission medium to bereceived and/or executed by the computer system 600. These signals,which might be in the form of electromagnetic signals, acoustic signals,optical signals and/or the like, are all examples of carrier waves onwhich instructions can be encoded, in accordance with variousembodiments of the invention.

The communications subsystem 630 (and/or components thereof) generallywill receive the signals, and the bus 605 then might carry the signals(and/or the data, instructions, etc. carried by the signals) to theworking memory 635, from which the processor(s) 605 retrieves andexecutes the instructions. The instructions received by the workingmemory 635 may optionally be stored on a storage device 625 eitherbefore or after execution by the processor(s) 610.

While certain features and aspects have been described with respect toexemplary embodiments, one skilled in the art will recognize thatnumerous modifications are possible. For example, while embodiments aredescribed above with regard to pavers and motor graders, it will beappreciated that the concepts presented here apply equally to a widevariety of heavy and construction equipment, including withoutlimitation any type of equipment that removes or places constructionmaterial to high accuracy, such as milling machines, concrete pavingmachines, slip-form paving machines, and the like. Further, the methodsand processes described herein may be implemented using hardwarecomponents, software components, and/or any combination thereof.Further, while various methods and processes described herein may bedescribed with respect to particular structural and/or functionalcomponents for ease of description, methods provided by variousembodiments are not limited to any particular structural and/orfunctional architecture but instead can be implemented on any suitablehardware, firmware and/or software configuration. Similarly, whilecertain functionality is ascribed to certain system components, unlessthe context dictates otherwise, this functionality can be distributedamong various other system components in accordance with the severalembodiments.

Moreover, while the procedures of the methods and processes describedherein are described in a particular order for ease of description,unless the context dictates otherwise, various procedures may bereordered, added, and/or omitted in accordance with various embodiments.Moreover, the procedures described with respect to one method or processmay be incorporated within other described methods or processes;likewise, system components described according to a particularstructural architecture and/or with respect to one system may beorganized in alternative structural architectures and/or incorporatedwithin other described systems. Hence, while various embodiments aredescribed with—or without—certain features for ease of description andto illustrate exemplary aspects of those embodiments, the variouscomponents and/or features described herein with respect to a particularembodiment can be substituted, added and/or subtracted from among otherdescribed embodiments, unless the context dictates otherwise.Consequently, although several exemplary embodiments are describedabove, it will be appreciated that the invention is intended to coverall modifications and equivalents within the scope of the followingclaims.

What is claimed is:
 1. A heavy equipment vehicle, comprising: alocomotion system configured to move the heavy equipment vehicle; a toolconfigured to manipulate a ground surface continuously as the heavyequipment vehicle moves; a communication interface to providecommunication with a plurality of position measurement devices; and acontrol system comprising a processor, a non-transitory storage medium,and a set of instructions executable by the processor, the set ofinstructions comprising: instructions to receive position data from twoor more position measurement devices, including a first positionmeasurement device and a second position measurement device;instructions to control operation of the tool based on determinedpositions of the tool and a model stored on the non-transitory storagemedium; instructions to determine a first position of tool based onposition data received from the first position measurement device;instructions to transition from the first position measurement device tothe second position measurement device without interrupting movement ofthe heavy equipment vehicle or manipulation of the ground surface andwithout introducing a discontinuity in the manipulated ground surfacegreater than a specified threshold value; and instructions to determinea second position of the tool based on position data received from thesecond position measurement device.
 2. The heavy equipment vehicle ofclaim 1, wherein the set of instructions further comprises instructionsto provide a user interface for the control system.
 3. The heavyequipment vehicle of claim 2, wherein the set of instructions furthercomprises instructions to display, on the user interface, informationabout the two or more position measurement devices.
 4. The heavyequipment vehicle of claim 3, wherein the information about the two ormore position measurement devices comprises a distance to each of thetwo or more position measurement devices.
 5. The heavy equipment vehicleof claim 3, wherein the information about the two or more positionmeasurement devices comprises a location of each of the two or moreposition measurement devices.
 6. The heavy equipment vehicle of claim 3,wherein the information about the two or more position measurementdevices indicates which of the two or more position measurement devicesare providing position data used to determine a current position of thetool.
 7. The heavy equipment vehicle of claim 3, wherein the set ofinstructions further comprises instructions to receive, through the userinterface, input indicating which of the two or more positionmeasurement devices should be used to determine a current position ofthe tool.
 8. The heavy equipment vehicle of claim 2, wherein the set ofinstructions further comprises instructions to receive, through the userinterface, input specifying the threshold value.
 9. The heavy equipmentvehicle of claim 8, wherein the input specifies a horizontal threshold.10. The heavy equipment vehicle of claim 8, wherein the input specifiesa vertical threshold.
 11. The heavy equipment vehicle of claim 8,wherein the input specifies a distance threshold that defines a lineardistance over which any discontinuity is absorbed.
 12. The heavyequipment vehicle of claim 1, wherein the set of instructions comprisesinstructions to select one or more of the two or more positionmeasurement devices from which to receive position data.
 13. The heavyequipment vehicle of claim 1, wherein the heavy equipment vehicle is atractor.
 14. The heavy equipment vehicle of claim 13, whereinmanipulating a ground surface comprises forming the ground surface. 15.The heavy equipment vehicle of claim 13, wherein manipulating a groundsurface comprises moving the ground surface.
 16. The heavy equipmentvehicle of claim 13, wherein manipulating a ground surface comprisescompacting the ground surface.
 17. The heavy equipment vehicle of claim13, wherein the tool comprises a scraper blade, and wherein set ofinstructions further comprises instructions to orient the scraper blade.18. The heavy equipment vehicle of claim 13, wherein the locomotionsystem comprises a plurality of tracks, and wherein controllingoperation of the locomotion system comprises controlling steering of oneor more of the tracks.
 19. The heavy equipment vehicle of claim 18,wherein the set of instructions further comprises instructions toreceive, through a user interface, input to manually modify a steeringof one or more of the tracks.
 20. The heavy equipment vehicle of claim1, wherein manipulating the ground surface comprises removing materialfrom the ground surface.
 21. The heavy equipment vehicle of claim 1,wherein the set of instructions further comprises instructions tocontrol operation of the locomotion system.
 22. A control system for aheavy equipment vehicle, the control system comprising: one or moreprocessors; and a non-transitory computer readable medium incommunication with the one or more processors, the computer readablemedium having encoded thereon a set of instructions executable by thecomputer system to: receive position data from two or more positionmeasurement devices, including a first position measurement device and asecond position measurement device; control operation of a locomotionsystem of the heavy equipment vehicle and a tool of the heavy equipmentvehicle to manipulate a ground surface continuously, based on determinedpositions of the tool and a model stored on the non-transitory computerreadable medium; determine a first position of the tool based onposition data received from the first position measurement device;transition from the first position measurement device to the secondposition measurement device without interrupting movement of the heavyequipment vehicle or manipulation of the ground surface and withoutintroducing a discontinuity in the ground surface greater than aspecified threshold value; and determine a second position of the toolbased on position data received from the second position measurementdevice.
 23. A method, comprising: manipulating a ground surface with aheavy equipment vehicle, the heavy equipment vehicle comprising: alocomotion system configured to move the heavy equipment vehicle; a toolconfigured to manipulate a ground surface continually as the heavyequipment vehicle moves; a communication interface to providecommunication with a plurality of position measurement devices; and acontrol system configured to control operation of the heavy equipmentvehicle; receiving, with the control system, position data from two ormore position measurement devices, including a first positionmeasurement device and a second position measurement device;controlling, with the control system, operation of the locomotion systemand the tool based on determined positions of the tool and a modelstored on the non-transitory storage medium; determining, with thecontrol system, a first position of the tool based on position datareceived from the first position measurement device; transitioning, withthe control system, from the first position measurement device to thesecond position measurement device without interrupting movement of theheavy equipment vehicle or manipulation of the ground surface andwithout introducing a discontinuity in the manipulated ground surfacegreater than a specified threshold value; and determining a secondposition of the tool based on position data received from the secondposition measurement device.